Project Summary Cancer chemotherapy-induced peripheral neuropathy (CIN) is the most prevalent neurological complication of cancer treatment. It is a major side effect of the most frequently administered chemotherapy (CTX) drugs. While epidemiologic studies are limited, clinical experience suggests that CIN occurs in a large percentage of patients and has a significant impact on patients'ability to function and quality of life. In addition, effective treatments for CIN are not available at the present time. This study will be conducted in two parts. In Part 1, using a sample of patients with (n=400) and without (n=200) CIN who have completed CTX, differences in phenotypic (i.e., sensory characteristics, motor characteristics, mood, concurrent symptoms, balance, quality of life) and genotypic characteristics (i.e., candidate gene studies) will be evaluated. In Part 2, based on recent work from our group that demonstrated the efficacy of photon stimulation in improving sensation and quality of life in patients with painful diabetic peripheral neuropathy, we will conduct a pilot study to determine effect sizes for the effects of photon stimulation compared to placebo in improving light touch sensation, pain intensity, and pain qualities in oncology patients with CIN who have completed CTX. In addition, we will determine the feasibility of the treatment protocol and the safety of photon stimulation in patients with CIN. Patients will be treated with eight photon stimulation or placebo treatments over a period of 14 days. Subjective and objective measures will be done at baseline and prior to each of the treatments on days 2, 4, 6, and 8. Data from this pilot study will be used to determine if a large scale randomized clinical trial of photon stimulation is warranted for CIN. PUBLIC HEALTH RELEVANCE: Project Narrative Numbness, tingling, and pain in the hands and feet following the administration of chemotherapy (also called chemotherapy-induced neuropathy (CIN)) is a common problem in oncology patients. However, more information is needed on why patients develop neuropathy and how it impacts their mood, ability to function, and their quality of life. In addition, effective treatments for this problem are not available at the present time. This study will be conducted in two parts. In Part 1, patients who have finished chemotherapy and did or did not develop CIN will be evaluated to determine why some patients do and other patients do not develop CIN. In addition, the impact of CIN on patients'mood, function, and quality of life will be evaluated by comparing patients'reports on these important outcome measures. In addition, genetic markers that contribute to or protect against the development of CIN will be evaluated. Part 2 of this study will test the effects of a new treatment called photon stimulation (also called infrared light therapy) compared to placebo treatment to improve sensations in the feet of oncology patients with CIN.